Process for the manufacture of nitric acid or nitrates from nitrogen oxids.



, nut sraaras ra sin ALEXAEDER CLASSEN, QF AAOHEN, GERMANY.

ZPRZDCESS FOR THE MANUFACTURE OF NITRIC ACID 0R NITRATES FROM NITROGEN Patented Apr. 4t, 1916.

OXIDS.

1 1 g q Specification of'Lettcrs Patent.

Ztl'o Drawing.

To all whom it may concern I Be it known that I, ALEXANDER CLAssEN, a subject of the German Emperor, and resident of Aachen, Germany, have invented certain new and useful Improvements in Processes for the Manufacture of Nitric Acid or Nitrates from Nitrogen Oxide, of which-the following is a specification.

In hitherto known processes for themanufacture of nitric acid by direct conversion of nitrogen oxide (NO, NO,, N,O N 0,) which can be obtained by the action of electric discharges on a mixture of nitro' gen and oxygen, and which contain less than 74% of oxygen which is the oxygen content of nitrogen pentox'id (N 0,) there. is produced, in addition to nitric acid, also nitrous acid, or in addition to nitrate, also nitrite? according as the gases are conveyed into an aqueous or an alkaline liquid. The process is represented by the following equations The present process relates to the conversion of nitrogen oxide, Whether they be obtained by the action of suitable voltaicf arcs or by oxidation of ammonia, or in some other way, into a pure nitric acid or nitrate. The said conversion can be obtained accord ing to this invention by carrying out the further oxidation of nitrogen oxids in the presence of suitable catalyzers. As catalyzers there may be used for instance metalliccobalt and nickel, as well as the various oxid compounds of the said metals, preferably their nitrates.

The catalyzers (or-catalysts) are preferably used on suitable supportssuch as ashes tos-wool, asbestos-cardboard, magnesia, ciay, etc. If it is desired to use oxids, it is advisable to impregnate the supports with solutionsof the corresponding nitrate, and then to calcine with admission of air. The nitrates are placed on the supports preferably in an aqueous or alcoholic solution, the dry- 7 ing being carried out at 100-120; The rocess is for instance carried out by passmg a mixture of nitrogen oxids with a gase- Application filed Febr'uary 14, 1916. Serial No. 78,5 7

ous oxidizing agent such as oxygen or suitable oxygen-containing gas mixtures, through a tube filled with the'contact mass,

of the nitrogen o'xids. The process is preferably carried out for'instance by passing nitrogen oxide of any desired origin, mixed with oxygen which has been rendered active for instance by passing it through a Siemenss ozone battery, through a tube" charged with suitable contacts, for instance nickel nitrate contacts. The quantity of oxygen mustbe of course calculated so that it is'sufiicient for complete oxidation of the nitrogen oxids to (theoretically) N 0,. The as escaping from the contact tube, is colected in the well-known manner either in water or in an alkaline aqueous liquid, In.

the former case a pure nitric acid is obtained, in the seconda pure nitrate.

When workin in accordance with the foregoing examp e, the catalytic oxidation takes place at an ordinary temperature. For

comprises bringing a gaseous oxidizing agent andnitrogen oxids containing less than 74% of oxygen into contact with an oxidizing catalystand contacti the nitr0- gen pentoxid in the-resulting gas mixture,

with an alkaline aqueous liquid. A process of making nitric acid anhy drid which compnses' brmgmg a gaseous oxidizing agent and nitrogen oxide containing less than 74%" of oxygen into contact with an oxidizin r catalyst.

3. A process 0 making nitricacioi anhydrid which comprises bringingfa mixture. comprising oxygen and nitrogen oxide containing less than 74% of oxygen into eondrid which compr'rses bringing ami xture' 4. A process of making nitric acid anhydrid which comprises bringin'g, a; mixture comprising oxygen, ozone and nitrogen oxide containing less than 74% of oxygen? into contact withan oxidizing .catalyst,:; 4 5. A processof making nitric acid anhy drid which comprises bringing a 'mixturt comprising oxygen and nitrogen oxide was:

taining less than 74% of oxygen into ce ts I with an oxidizing catalyst containing i k y.

6. A process of making nitric acid anhydrid which comprises bringing a mixture comprising oxygen and nitrogen oxids containing less than 74% of oxygen into Contact With'a catalytic nickel-oxygen compound. I

7. A process of making nitric acid anhydrid which comprises bringing a mixture comprising oxygen and nitrogen oxids containin less than 74% of oxygen into contact a with nickel nitrate.

S. process of making nitric uCNl anhydri'd which comprises bringing a mixture comprising oxygen, ozone and nitrogen oxids containing less than 7%% of oxygen into contact with an oxidizing catalyst containing' ni ckel;

9. A process of making nitric acid anhy- 

